Visual display system

ABSTRACT

A visual display system including a display unit for simultaneously displaying the individual characters of a word unit. A selector switch is operative to select any one of a plurality of messages, each message consisting of one or more word units which are separately stored in the memory locations of a memory bank. Logic means responsive to the selector switch sequentially activates individual ones of the memory locations in accordance with the selected message. Finally, a character generator receives the output of the memory bank and activates the display unit, a character at a time, until the entire word unit appears, whereupon the memory bank signals the logic means to activate the next memory location in accordance with the selected message.

llite tates tet n 1 irrgan et al.

11] 3,750,,i3l 1 1 .iniy 3Ll973 VISUAL DISPLAY SYSTEM [75] Inventors: haul G. Burgan,Anaheim; Richard 3. Jekiel, Orange, both of Calif.

[73] Assignee: Richard G. Wentworth, Orange,

Calif.

22 Filed: Dec. 17, 1971 [21] App]. No.: 209,046

[52] U.S. Cl. 340/334, 340/332, 340/339 [51] int. Cl. G081) 5/36 [58] Field oi Search 340/334, 339

[56] References Cited UNITED STATES PATENTS 3,594,778 7/1971 Herald et al. 340/334 X 3,273,140 9/1966 Foster et a1 340/334 3,388,391 6/1968 Clark 340/324 AD 3,432,846 3/1969 Jones et al. 340/339 3,493,956 2/1970 Andrews et al..... 340/334 3,638,217 1/1972 Sutherland 340/324 R X Primary Examiner--David L. Trafton Attorney-Philip M. Hinderstein [57] ABSTRACT A visual display system including a display unit for simultaneously displaying the individual characters of a word unit. A selector switch is operative to select any one of a plurality of messages, each message consisting of one or more word units which are separately stored in the memory locations of a memory bank. Logic means responsive to the selector switch sequentially activates individual ones of the memory locations in accordance with the selected message. Finally, a character generator receives the output of the memory bank and activates the display unit, a character at a time, until the entire word unit appears, whereupon the memory bank signals the logic means to activate the next memory location in accordance with the selected message.

9 Claims, 2 Drawing Figures ViSUAlL DISPLAY SYSTEM BACKGROUND OF THE INVENTION l. Field of the invention The present invention relates to a visual display system and, more particularly, to a mobile command and control system enabling vehicles, such as law enforcement vehicles, to communicate readily with other vehicles or pedestrians.

2. Description of the Prior Art Moving vehicles presently have no means for effectively communicating messages, commands and/or control signals to other vehicles or pedestrians. One area where this situation is particularly critical is in law enforcement. A law enforcement officer has limited means to warn civilians of impending problems or emergency hazards ahead. Existing law enforcement vehicles simply have sirens and lights and the officer must start signalling from behind an offending vehicle, presenting the hazardous situation of obtaining, from the rear, the attention of a driver looking ahead. in addition, an ofiicer can effectively control only one offending vehicle at a time and has only one command at his disposal. Such a system simply is ineffective in permitting the officer to warn civilians of impending problems such as fog, ice, a vehicle pile-up, blocked traffic lanes, and the like.

Other types of vehicles would also benefit from the availability of a visual display system, although the need for these other uses is far less critical than that involved in law enforcement. For example, a visual display system could be used on commercial vehicles such as taxicabs and buses for advertising purposes.

Several systems have been proposed in the past for solving this problem. For example, U. S. Pat. Nos. 2,968,025 and 3,226,707 to WilburD. Owens and Herman Newman et al., respectively, disclose automobile message indicators including a changeable sign mounted on the vehicle roof or behind the rear window. The sign consists of an endless tape carrying a number of messages, one of which is selected by use of a switch box positioned adjacent the dashboard. A motor is used to drive the endless tape until the selected message appears.

Although this type of system is available, it has obtained no significant degree of acceptance because of the many problems associated therewith. in the first instance, because of space limitations and the fact that an endless tape is utilized, there is usually a very limited number of messages. Secondly, since the display is generated by a light. shining through the message-bearing tape, visibility is usually limited. Furthermore, if it is desired to add a new message, delete an existing message, or change a message, it is necessary to change the entire tape. A very significant limitation results from the fact that any sign of this type must be mounted at the rear of the vehicle in such a manner that it will not obstruct the driver's visibility. Since the vertical height of the sign is limited, so is the length of the message. More specifically, if the number of words in the message is increased, the only manner of presently displaying the increased message is to decrease the size of the individual words. This presents a substantial visibility problem.

There are also numerous types of electronic visual display systems but none of these systems have been effectively applied to a moving vehicle. Most existing electronic display systems have a limited message capacity. Furthermore, because present uses do not create space and power limitations, existing electronic systems are large, cumbersome, and complex. Such systems are typically used with incandescent or neon lamps which require a substantial amount of power and render them unsuitable for use in a mobile vehicle where the power drain must be minimized.

SUMMARY OF THE lNVENTlON According to the present invention, there is provided a visual control system which is ideally suited for use on a moving vehicle for providing communications between the driver of the vehicle and other vehicles or pedestrians. The present system uses all electronic components and effectively eliminates all of the problems inherent in existing mechanical devices using messagebearing tapes. The present system has the capability of displaying a large number of messages in a manner which is highly visible. With the present system, individual messages may be changed without interferring with the remainder of the messages. With the present system, there is the additional capability of displaying a message consisting of any number of words without limiting the size of the individual words. This is achieved by displaying the words sequentially rather than simultaneously, so that each word of the message is displayed at full size, giving maximum visibility.

The present visual display system is also effective in overcoming the problems inherent in existing electronic display systems. More specifically, the present visual display system not only has a large message capacity, but the apparatus required to activate the display is small and easy to use and easily positioned at any suitable location within the vehicle. The present system uses an available type of display in which each word is energized a character at a time thereby substantially minimizing power requirements. Finally, the number of messages which need to be stored is minimized because of the present systems capability of storing only words and using each of such words in more than one message.

Briefly, the present visual display system includes a display unit for simultaneously displaying the individual characters of a word unit. A selector switch is operative to select any one of a plurality of messages, each message consisting of one or more word units which are separately stored in the memory locations of a memory bank. Logic means responsive to the selector switch sequentially activates individual ones of the memory locations in accordance with the selected message. Finally, a character generator receives the output of the memory bank and activates the display unit, a character at a time, until the entire word unit appears, whereupon the memory bank signals the logic means to acti vate the next memory location in accordance with the selected message.

it is therefore an object of the present invention to provide a novel visual display system.

It is a further object of the present invention to provide a mobile message display system for communicating with other vehicles or pedestrians.

it is a still further'object of the present invention to provide a visual display system having a significantly large message capacity.

it is another object of the present invention to provide a visual display system including all electronic components which minimizes power and memory requirements.

It is still another object of the present invention to provide a visual display system in which the several words of a given message are displayed sequentially rather than simultaneously.

Another object of the present invention is the provision of a visual display system for displaying any one of a large number of messages in which individual messages may be changed without interfering with the remaining messages.

Still other objects, features, and attendant advantageS of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment constructed in accordance therewith, taken in conjunction with the accompanying drawings wherein like numerals designate like parts in the several figures and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation, partially in block diagram form, of the present visual display system; and

FIG. 2 is a more detailed block diagram of the apparatus included within the visual display system of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and, more particularly, to FIG. 1 thereof, the present visual display system, generally designated 10, includes three major sections, namely, a manual control unit 20, a decoder 30 and a display unit 40. Manual control unit 20 is, as shown, a small, relocatable, operator control panel which is used to select pre-programed messages to be displayed. For this purpose, manual control unit 20 includes a message selector 21 which may be a simple rotary switch 22 having a large number of positions, each of such positions corresponding to a different message. By way of example, twenty-five positions for rotary switch 22 are shown in FIG. 1.

The output of message selector 21, indicating the selected message, is applied to a message indicator 23. According to one embodiment of the present invention, message indicator 23 may be a mechanical device including a drum 24 having a number of slots therein corresponding to the number of positions of switch 22. Drum 24 would be rotatably mounted in such a manner that one of the slots is visible, at all times, through a window 25. By positioning a message card in each of the slots in drum 24, each card containing a message corresponding to the switch positions of selector 2], and by rotating drum 24 with switch 22, the operator will be able to see the message corresponding to the position of switch 22. Alternatively, message indicator 23 could be an electronic display system of a type known by those skilled in the art.

Finally, manual control unit 20 also includes a series of buttons and switches corresponding to desired functions. For example, manual control unit 20 may include a first button 26 which may be utilized to signal the remainder of visual display system I that the message has been selected and that it is ready to be displayed. Manual control unit 20 may also include a second button 27 which the operator may activate to signal decoder 30 that the selected message is to be repeated at specified intervals. Finally, manual control unit 20 may also include an on off switch 28 for conducting power to manual control unit 20, decoder 30, and display unit 40.

According to the preferred embodiment of the present invention, manual control unit 20 is implemented using conventional electronic logic using the simplified logic levels I and 0. Therefore, message selector 21 would have a plurality of lines connected between itself and decoder 30, the number of lines :epending upon the capability thereof. By way of example, if the logic associated with message selector 21 has five output lines connected to decoder 30, this will provide manual control unit 20 with the capability of selecting a message out of a group of 32. With respect to button 26, this may be implemented with a single control line connected to decoder 30 whereupon the change of state thereof would indicate that a message is to be displayed. Button 27 would also be implemented with a single control line which, when activated, commands decoder 30 to repeat the selected message at a specified interval.

Decoder 30 provides all the decision, memory, and scanning functions of visual display system 10 and translates the manually selected commands from control unit 20 into a form suitable for operating display unit 40. As will be explained more fully hereinafter, the message selected by manual control unit 20 may consist of one or more word units, where each word unit consists of one or more words up to a maximum number of letters or characters. More specifically, display unit 40 will have the capability of displaying a given number, such as 12, letters or characters. Therefore, each word unit would consist of one or more words having up to twelve characters. For example, a single word unit may consist of the word CAUTION in which each of the seven letters thereof constitutes a character. On the other hand, a word unit could consist of the words ICE AHEAD" in which the eight letters and the space therebetween represent the characters. However, the mesages displayed by unit 40 need not, in accordance with the present invention, consist of a single word unit. For example, it may be desired to display the message CAUTION ALL TRAFFIC MERGE RIGHT". In this case, the message would consist of three word units, the first word unit consisting of the characters CAUTION", the second word unit consisting of the characters ALL TRAFFIC", and the third word unit consisting of the characters MERGE RIGHT. Decoder 30, therefore, includes a memory including a plurality of memory locations wherein each of the memory locations stores the characters of one of the word units. Decoder 30 also includes logic means for acting on the selected position of switch 22 and for sequentially activating individual ones of the memory locations in order to read out, in the desired order, the word units needed to form the selected message. The result is that the series of word units are serially fed from decoder 30 to display unit 40. Furthermore, within each word unit, the characters thereof are also supplied to display unit 40 one at a time. As will appear more fully hereinafter, this approach permits the minimizing of both the memory capability of decoder 30 and the power drawn by display unit 40.

Display unit 40 consists of a number of display elements 4], each of which is capable of displaying a given character. By way of example, display unit 40 may include twelve display elements 41. According to the preferred embodiment of the invention and in order to achieve the objective of minimizing the power requirements of visual display system litl, each of display elements 41 is an electro-mechanical matrix of dots 42 arranged in a number of columns and rows. Each dot 42 consists of a thin, flat disc having a colored side and a dark side. Each such disc is rotatably mounted to expose one side or the other. Such discs are available on a pre-encoded module readout including any number of discs, such as the 5 X 7 array shown in PM]. 1. Such arrays are presently sold by Ferranti-llackard Limited of Ontario, Canada. in this type of an array, each display element consists of two parts, an indicator dot and an encapsulated coil assembly. The indicator dot, as explained previously, is a pivoted disc, free to rotate in a housing. The disc is permanently magnetized and is colored on one side and dark on the other. The coil assembly, not shown, consists of a U-shaped electro-magnet core with two coils wound around it, a set coil and a reset coil. There is no mechanical driving linkage between the electro-magnet and the magnetized disc in that magnetic forces provide the drive.

The particularly desirable feature of these display elements is that power is only required to change state. For example, assume that the disc has its colored side showing. The residual magnetism maintains the disc in this position until a pulse is applied to the reset coil whereupon the disc will flip to expose its dark side. The disc is now magnetically held in this position until changed by a pulse in the set coil. it is therefore apparent that the operator can select a message and continue to display the message for an indefinite period of time in spite of the fact that power is only required during the actual process of setting up the message on display unit 40.

Another desirable feature of this type of display element is that they are highly visible. Dots are presently available having a diameter of k inch and having one side colored a bright orange. Where such dots are used, they are easily visible for at least 500 feet. In addition, to increase visibility under poor weather conditions, such as in the case of fog, display system 1411 may include a black light (not shown) mounted adjacent display unit 40 to shine on each of display elements 41.

Referring now to FIG. 2, a preferred embodiment of decoder 30 includes several major elements, namely, input command logic and memory select 31, a memory bank 32, a character generator 33, a column sequencer 34, a character sequencer 35, and a synchronizing clock 36. As explained previously, decoder 311 provides all decision, memory, and scanning functions of visual display system 1b. The function of elements 31-36 is to translate the manually-selected commands from control unit into a form suitable for operating the type of display unit 40 discussed previously.

As explained previously, the message selected by manual control unit 20 may consist of one or more word units. Where this is the case, display unit 40 may be implemented in several different ways. For example, if it were desired to be able to display a message having up to three word units such as CAUTION ALL TRAFFlC MERGE RIGHT", it would be possible to include in display unit 40 three rows of display elements 41. However, this is considered to be undesirable for several reasons. if visual display system W is to be used as a mobile traffic command and control system for law enforcement vehicles, it is necessary that display elements 41 be visible for as much as 500 feet. For this to be the case, each of display elements d1 must be relatively large. On the other hand, there is a limit to the vertical space available at the back of a law enforcement vehicle. According to the preferred physical construction of the present invention, display elements 11 are mounted at the rear of the vehicle so as to be above the rear lights, but below the bottom of the rear window, so as to not interfere either with the officers visibility or the normal vehicle signals. Therefore, as a practical matter, in order to satisfy both the requirements of high visibility and the space available, it is the teaching of the present invention that only a single row of display elements 41 is to be included. Therefore, if it is desired to display a message including multiple word units, the individual word units are displayed sequentially rather than simultaneously. Such an approach also satisfies another requirement of a mobile display system, namely that of minimizing the memory capacity required for the system. For example, by separately storing a small number of word units, a large number of messages may be displayed by selecting vari' ous combinations of such word units.

The individual word units are stored in memory bank 32. More specifically, memory bank 32 has a plurality of memory locations where each memory location stores the characters of one word unit. By way of example, memory bank 32 may be composed of l6 individual memory locations, each location having the capability of storing a sufficient number of data bits to activate each of the 12 display elements 41 of display unit dill. More specifically, display element 41 was previously described as including a 5 X 7 array of dots 42, a total of 35 dots. Since six bits are required to completely define 35 different decisions, each memory location in memory bank 32 would have at least 12 six-bit memory cells. As a practical matter, each of the 12 memory cells would have more than a six-bit capability, the additional bits being used for signaling purposes, as will be described more fully hereinafter. In any event, it is significant here to note that since each word unit is stored in a different memory location within memory bank 32, the individual word units stored within memory bank 32 may be readily changed without affecting the remaining word units stored therein.

Input command logic and memory select 31 includes conventional logic circuitry for acting on the selected position of message selector 21 and for sequentially activating individual ones of the memory locations in memory bank 32 in order to read out, in the desired order, the word units needed to form the selected message. For this purpose, input command logic and memory select 31 includes a memory device connected to the output lines of message selector 21. Stored within such memory device would be the pre-programed information needed to activate memory bank 32. For example, assume that position 20 of switch 22 of message selector 21 calls for the message CAUTION ALL TRAFFllC MERGE RIGHT". Also assume that the word unit CAUTlON" is stored in memory location two of memory bank 32, that the word unit ALL TRAFFIC is stored in memory location six of memory bank 32, and that the word unit MERGE RlGl-lT" is stored in memory location nine of memory bank 32. Therefore, when switch 22 is turned to position "20, the logic and memory device within element 31 determines that memory locations two, six, and nine must be sequentially activated, in that order, in order to display the desired message. Therefore, the memory device within element 31 need only be a simple, preprogramed assembly which specifies the start location of a particular message and additional memory locations, if needed.

The outputs of display message button 26 and flash message button 27 are also applied to input command logic and memory select 31. Therefore, input command logic and memory select 31 does not start the sequential activation of the memory locations within memory bank 32 until a suitable signal is received from display message button 26. in addition, if input command logic and memory select 31 receives a signal from flash message button 27, it will proceed to reactivate the memory locations in memory bank 32 at predetermined time intervals.

As shown in FIG. 2, input command logic and memory select 31 has a plurality of output lines 50, the number of output lines 50 corresponding to the number of individual memory locations in memory bank 32. In this manner, input command logic and memory select 31 is operative to activate a given memory location by activating the input line thereto. Memory bank 32 has a first series of output lines 51 which receive the bits necessary to define the characters of the word unit stored therein. According to the present example, six bits are required to define each character since each character consists of 35 dots 42. For reasons which will appear more fully hereinafter, when one of memory locations within memory bank 32 is activated, memory bank 32 applies to output lines 51 the bits necessary to define the first character of the word unit stored therein, these six bits being applie: to character generator 33.

Character generator 33 is a standard off-the-shelf device which provides an output suitable to control a X 7 dot matrix. More specifically, character generator 33 has a plurality of output lines 52, one for each row of display elements 41. In the present embodiment, since each of display elements 41 has seven rows, character generator 33 has seven output lines 52 which are connected to the row input 43 of display elements 41. By changing the logic levels on output lines 52, row input 43 determines whether a pulse is applied to the set or reset input of each of dots 42 in each of the rows of display elements 41.

In order to control the individual columns of dots 42 of display elements 41, display unit 40 also includes a column input 44 which is operative to energize only a single column at a time. Therefore, character generator 33 is operative to apply to output lines 52 information necessary to define only one column of dots 42 at a time.

Character generator 33 is controlled by a column sequencer 34 which receives C, clock pulses from a clock pulse generator 36. More specifically, clock generator 36 applies a train of C, clock pulses to column sequencer 34 which applies a first output over a line 53 simultaneously to character generator 33 and column input 44 of display 40. Accordingly, as soon as the data bits from memory bank 51 are applied to character generator 33 to define the first character of the selected word unit, column sequencer 34 signals character generator 33 to apply to output lines 52 the row data for the first column of the first display element 41.

This same signal simultaneously energizes the first column of dots 42 of the first display element 41. Upon the occurrence of the second C, clock pulse from clock generator 36, column sequencer 34 simultaneously signals character generator 33 and column input 44 to apply the row and column data to display elements 41 for the second column of the first display element 41. This continues until the fifth C clock pulse from clock generator 36 causes column sequencer 34 to signal character generator 33 and column input 44 to activate the fifth column of the first display element 41 of display 40. Upon the conclusion of the fifth clock pulse, character generator 33 applies a signal over a line 54 to memory bank 32 to signal the appropriate memory location therein to apply to character generator 33 the six data bits required to define the second character of the selected word unit. Since this transfer of infonnation between memory bank 32 and character generator 33 may occur between consecutive C clock pulses, character generator 33 is ready, upon the occurrence of the sixth C clock pulse from column sequencer 34 and clock 36, to apply to row input 43 the row data required to define the first column of the second display element 41 of display 40.

Column sequencer 34 also applies, after every five C clock pulses, a signal on a line 55 to character sequencer 35. Accordingly, after the fifth clock pulse from column sequencer 34, character sequencer 35 is activated to signal column input 44 of display 40 that the next five pulses from column sequencer 34 are to be applied to the second display element 41. In other words, when column sequencer 34 advances to the fifth count of each character, the logic therein increments character sequencer 35 by one count simultaneously with character generator 33 calling up a new character address from the memory location in memory bank 32. It should be noted that this approach, utilizing both a column sequencer 34 and a character sequencer 35, significantly reduces the number of interface lines between decoder 30 and display unit 40. If only a column sequencer 34 were utilized, 60 output lines would be required between column sequencer 34 and column input 44, such 60 lines corresponding to the five columns of each of the 12 display elements 41. However, with the present approach, these 60 lines are reduced to 17, five of these lines between column sequencer 34 and column input 44 to control the five columns of each of elements 41 and 12 lines between character sequencer 35 and column input 44 to select the appropriate display element 41.

It should be mentioned that even though decoder 30 applies row data to display elements 41 one column at a time for a total of 60 columns, the resultant display of display unit 40 does not so appear. Obviously, the reason for this is that the data is applied to display elements 41 at such a rigid rate that it appears to the eye that all characters of display 40 are energized simultaneously.

As just described, when column sequencer 34 advances to the fifth count, the logic therein increments character sequencer 35 by one count. Simultaneously, character generator 33 signals memory bank 32, over line 54, to apply to output lines 51 the six data bits required to define the next character of the selected word unit. Upon completion of a full display scan, when memory bank 32 has applied to character generator 33 the last character of the word unit stored therein, memory bank 32 applies a signal over a line 56 to input command logic and memory select 31 to indicate that the word unit stored therein has been displayed. At this time, the function of input command logic and memory select 31 will depend upon the inputs applied thereto from message selector 21 and flash message 27. If, for example, the message selected using switch 22 had only a single word unit and if flash message 27 had not been activated, input command logic and memory select 31 would terminate operation of the remaining components of decoder 30 and the message now displayed on display unit 40 would simply remain. Therefore, once the dot pattern has been set up, no power is required to hold that state. On the other hand, if the message selected by switch 22 had more than one word unit, the signal on line 56 to input command logic and memory select 31 would be interpreted thereby as requiring a predetermined pause, such as for one second, and then the activation of the memory location in memory bank 32 containing the second word unit of the selected message. This procedure would repeat until the last word unit had been displayed whereupon input command logic and memory select 31 would automatically repeat the sequence.

In the event that the message selected by switch 22 has more than one word unit, the appearance of display 40 will automatically flash because of the sequential display of such word units. However, flash message button 27 also permits flashing of messages containing only a single word unit. More specifically, in the event that message selector 21 signals only a single word unit and if button 27 is activated, the signal on line 56 from memory bank 32 will be interpreted by input command logic and memory select 31 as requiring a pause, followed by a resetting of all display elements 41, followed by a repeat of the entire sequence.

Resetting of display elements 41 to completely blank display 40 may be achieved in several ways. For example, one of the memory locations within memory bank 32 may contain a word unit consisting of a completely blank message. Therefore, any time it is required to flash a message, input command logic and memory select 31 may simply alternatebetween the memory location containing the desired message and the memory location containing the blank message.

lnput command logic and memory select 31 may be synchronized with theremainder of decoder 30 by the output of clock 36; More specifically, input command logic and memory select 31 may receive, over a line 57, a train of C, clock pulses which have the same frequency as the C clock pulses butwhich may be 180' out of phase with the C, clock pulses so that input command logic and memory select 31- performs its switching operationsbetween clock periods of memory bank 32, character generator 33, column sequencer 34,.and character sequencer 35.

Summarizing the operation of visual display system 1111, switch 22 of message selector 21 inmanual control unit is capable of selecting any one of a large number of messages. As selector switch 22 is rotated, the message corresponding to the various positions of switch22 is displayed within window of message indicat'or 23. When the desired message appears within window 25, the operator activates display message button 26 and, optionally, flash message button 27. The output of manual control unit 20 is applied to decoder which provides all of the'decision, memory, and

scanning functions of visual display system 111. The message selected by manual control unit 20 may consist of one or more word units, each such word unit consisting of one or more words up to a maximum number of 12 characters. The individual word units are stored within the memory locations in memory bank 32, memory bank 32 being composed of 16 individual 72 bit memory cells, each in a 12 character by six bit per character configuration. A unique feature of memory bank 32 is that it is field programmable in that ony one of the word units may be changed without affecting the remaining word units.

Input command logic and memory select 31 receives the signals from manual control unit 20 and selects the memory locations in memory bank 32 which contain the desired message. The memory portion of unit 31 is a pre-prograrnmed assembly which specifies the start location of a particular message as well as the additional message locations, if any. This procedure allows for minimizing of the memory capacity of decoder 30 in that a large number of messages may be formed from a relatively small number of word units.

Upon activation of display message button 26, input command logic and memory select 31 activates one of lines 50 corresponding to the memory location containing the first word unit of the selected message. Memory bank 32 immediately applies to output lines 51 the six bits required to define the first character of the selected word unit. Character generator 33 operates on this data and applies via lines 52 to row input 43 the row data for the first column of the first character of the selected word unit. It should be noted that character generator 33 and row input 43 activate all dots in a particular row at one time. However, the only row driver that will actually conduct is that one that is coincident with the enabled column and character drivers. Accordingly, clock 36 causes column sequencer 34 and character sequencer 35 to activate the first column of the first character of the first word unit of the selected message. Thereafter, clock 36 controls the sequencing of the first character through the next four columns. When the last column of the first character of the first word unit of the selected message is completed, column sequencer 34 signals character sequencer 35 to activate the second character whereupon character generator 33 simultaneously signals memory bank 32 to apply to lines 51 the data bits which define the second character. It should therefor be apparent that since only a single column of dots are activated at one time, a minimum amount of power is needed to set up the message on display elements 41.

When memory bank 32 receives a signal on line 54 indicating that character generator 33 has completed the display of the last character of the first word unit of theselected message, a signal is appliedover line 56 to input command logic and memory select 31 to perfon'n its next function. As explained previously, the next function may consist of deactivating all circuitry, activating the next word unit of the selected message, orreissuingthe pre-selected message at specified intervals.

It can therefore be seen that in accordance with the present invention, there is provided a visual displaysystem10 which is ideally suited for use on a moving vehiclefor providing communications between the driver of the vehicle and other vehicles or pedestrians. Visual display system 10 uses all electronic components and effectively eliminates all of the problems inherent in existing mechanical devices using message-bearing tapes. Visual display system has the capability of displaying a large number of messages in a manner which is highly visible. With system it), individual messages may be changed without interfering with the remainder of the messages simply by changing the information stored within one of the memory locations in memory bank 32 or one of the memory cells in the memory device in input command logic and memory select 31. With system 10, there is the additional capability of dis playing a message consisting of any number of words without limiting the size of the individual words. This is achieved by displaying the words of the message sequentially rather than simultaneously so that each word of the message is displayed at full size, giving maximum visibility.

Visual display system 10 is also effective in overcoming the problems inherent in existing electronic display systems. More specifically, visual display system 10 not only has a large message capacity, but the apparatus required to activate the display is small and easy to use and easily positioned at any suitable location within the vehicle. Visual display system 10 uses an available type of display 40 in which each word unit is energized a character at a time, each character being energized a column at a time, thereby substantially minimizing power requirements. Furthermore, once a given message has been set up, no power is required to retain the message. Finally, the number of messages which must be stored is minimized, thereby minimizing the capacity of memory bank 32, because of the present system s capability of storing word units rather than messages and using individual word units in more than one message.

While the invention has been described with respect to a preferred physical embodiment constructed in accordance therewith, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiment, but only by the scope of the appended claims. I

We claim:

1. A visual display system comprising:

display means including a limited number of display elements, one element for each character of a word;

means for selecting any one of a plurality of messages for display by said display means, at least some of said messages consisting of two or more word units, each of said word units consisting of a number of characters and spaces before, between, and after characters equal to the number of display elements in said display means, said display means being only capable of displaying one word unit at a time whereby said display means displays the word units of the selected message sequentially; directly addressable, prc-programmed, read-only memory means including a plurality of memory locations, each of said memory locations storing the characters of one of said word units; logic means interposed between said selecting means and said memory means for activating individual ones of said memory locations in accordance with said selected message, each of said memory locations being operative, upon activation, to sequentially apply to the output thereof the characters of the word unit stored therein; and

means interposed between said output of said memory means and said display means for sequentially applying the characters of said word units to said display means, said characters applying means being operative, upon completion of the application of each character to said display means, to signal said memory means to apply to the output thereof the next character of the word unit stored therein,

said memory means including feedback means being operative, upon completion of the application to said display means of the last character of each word unit, to generate a feedback signal to activate the next memory location to apply the characters of the word unit stored therein to the output thereof in accordance with said selected message.

2. A visual display system according to claim 1 wherein said logic means further comprises:

memory means for storing, for each of said messages,

the memory locations containing the word units required to form said message.

3. A visual display system according to claim 2 wherein said feedback signal is applied to said memory means in said logic means to select the memory location containing the next word unit in said selected message.

4. A visual display system according to claim 1 wherein said selecting means comprises:

manually controllable switch means having a plurality of positions corresponding to said plurality of messages; and further comprising:

mechanical means positioned adjacent said switch means for displaying visually the message corresponding to the positions thereof.

5. A visual display system according to claim 1 further comprising:

means operatively coupled to said logic means for signaling said logic means to repeat the selected message at predetermined intervals.

6. A visual display system according to claim 1 wherein said feedback means is further operative, upon completion of the application to said display means of the last character of the last word unit of said selected message, to generate a second feedback signal and to apply said second feedback signal to said logic means to signal the completion of the display of said selected message.

7. A visual display system according to claim 6 wherein said logic means is operative, upon receiving said second feedback signal, to alternatively deactivate said display system or re-activate said ones of said memory locations in accordance with said selected message at predetermined time intervals; and further comprising:

means associated with said selecting means for choosing whether said message is to be displayed once or is to be re-displayed at said predetermined time intervals.

8. A visual display system according to claim 1 wherein each of said display elements comprises a plurality of rows and columns of display units, each of said display units being selectively visible without the application of electrical power thereto, each of said display units only requiring power to change the state thereof.

9. A visual display system according to claim 8 wherein each of said display units consists of an indicator dot and an electro-magnetic drive assembly, each of said dots consisting of a thin, flat disc having a visible side and an invisible side and being rotatable to expose tem.

one side or the other, and wherein said electro- 

1. A visual display system comprising: display means including a limited number of display elements, one element for each character of a word; means for selecting any one of a plurality of messages for display by said display means, at least some of said messages consisting of two or more word units, each of said word units consisting of a number of characters and spaces before, between, and after characters equal to the number of display elements in said display means, said display means being only capable of displaying one word unit at a time whereby said display means displays the word units of the selected message sequentially; a directly addressable, pre-programmed, read-only memory means including a plurality of memory locations, each of said memory locations storing the characters of one of said word units; logic means interposed between said selecting means and said memory means for activating individual ones of said memory locations in accordance with said selected message, each of said memory locations being operative, upon activation, to sequentially apply to the output thereof the characters of the word unit stored therein; and means interposed between said output of said memory means and said display means for sequentially applying the characters of said word units to said display means, said characters applying means being operative, upon completion of the application of each character to said display means, to signal said memory means to apply to the output thereof the next character Of the word unit stored therein, said memory means including feedback means being operative, upon completion of the application to said display means of the last character of each word unit, to generate a feedback signal to activate the next memory location to apply the characters of the word unit stored therein to the output thereof in accordance with said selected message.
 2. A visual display system according to claim 1 wherein said logic means further comprises: memory means for storing, for each of said messages, the memory locations containing the word units required to form said message.
 3. A visual display system according to claim 2 wherein said feedback signal is applied to said memory means in said logic means to select the memory location containing the next word unit in said selected message.
 4. A visual display system according to claim 1 wherein said selecting means comprises: manually controllable switch means having a plurality of positions corresponding to said plurality of messages; and further comprising: mechanical means positioned adjacent said switch means for displaying visually the message corresponding to the positions thereof.
 5. A visual display system according to claim 1 further comprising: means operatively coupled to said logic means for signaling said logic means to repeat the selected message at predetermined intervals.
 6. A visual display system according to claim 1 wherein said feedback means is further operative, upon completion of the application to said display means of the last character of the last word unit of said selected message, to generate a second feedback signal and to apply said second feedback signal to said logic means to signal the completion of the display of said selected message.
 7. A visual display system according to claim 6 wherein said logic means is operative, upon receiving said second feedback signal, to alternatively deactivate said display system or re-activate said ones of said memory locations in accordance with said selected message at predetermined time intervals; and further comprising: means associated with said selecting means for choosing whether said message is to be displayed once or is to be re-displayed at said predetermined time intervals.
 8. A visual display system according to claim 1 wherein each of said display elements comprises a plurality of rows and columns of display units, each of said display units being selectively visible without the application of electrical power thereto, each of said display units only requiring power to change the state thereof.
 9. A visual display system according to claim 8 wherein each of said display units consists of an indicator dot and an electro-magnetic drive assembly, each of said dots consisting of a thin, flat disc having a visible side and an invisible side and being rotatable to expose one side or the other, and wherein said electro-magnetic drive assembly maintains said disc with one side or the other exposed without the application of power thereto, whereby said selected message may be maintained with no power applied to said display system. 